Three issues addressed here:
1. Dependency on dictionary iteration order
CharacterProperties.swift.gyb iterated a dictionary to produce its output.
Changed this to a list of tuples to ensure the order is predictable.
2. Python3 `map` returns an iterator, not a list
Changed a bunch of `map` calls to `list(map(...))` to ensure the result is a list
3. Python3 `int()` expects a string, won't accept a list of characters
Added a concatenation step that is effectively a no-op on Python2
…plus an attempt at reducing wide range of memory used between independent, repeated measurements in the `CharacterPropertiesPrecomputed` benchmark by reserving the appropriate set capacity in advance.
